Rechargeable batteries of the so-called “rocking chair” type are believed to be understood, in which a carbon material, for example graphite, is used as the anode material, which is able to intercalate lithium ions at the intercalation sites of its lattice planes formed by carbon atoms in the form of six-membered rings when charging is carried out. Typically, a lithium intercalation material, such as LiCoO2, LiNiO2 or LiMn2O4, is used as the active cathode material, which is able to deintercalate the lithium ions from their intercalation sites during charging so that lithium ions migrate back and forth between the intercalation electrodes during the charging/discharging cycles.
A metallic lithium anode is used as the anode in various types of lithium batteries, in particular the so-called post lithium-ion batteries, such as Li-sulfur or Li-oxygen. The problem of irregular lithium deposition occurs in this anode, so that the porosity and the volume of the entire lithium anode increase continuously after repeated dissolution and deposition processes of lithium metal. This enlarges the internal surface on which the parasitic side reactions with the electrolyte take place.
In order to prevent these effects, the lithium anode is usually covered with a lithium-ion-conducting protective layer (e.g., polymer ion conductor, solid ion conductor), which prevents contact between lithium and the electrolyte. Due to the volume movements in the lithium anode as a result of the dissolution and re-deposition of lithium, the protective layer must also continuously move together with the lithium surface. It is known from experimental tests that none of the presently known ion-conducting materials as the protective layer withstands these volume movements over numerous charging/discharging cycles. Rather, fractures and cracks develop, which significantly impair the function of the protective layer. As long as this problem persists, even a protective layer that conducts ions very well is not able to offer lasting protection to the lithium anode against the electrolyte.